Regarding formation of a channel stopper for increasing a withstand voltage of a semiconductor device, there is a known manufacturing method in which a laser beam is irradiated to a bottom surface of a groove where an impurity of a first conductivity type has been supplied in advance, thus introducing the impurity of the first conductivity type into a first semiconductor layer (see Patent Document 1). In the manufacturing method of Patent Document 1, it is possible to form the channel stopper by scanning the laser beam, so that a mask forming step becomes unnecessary.